The present invention relates to vaccine therapy for T-cell mediated diseases, and in particular to therapeutic preparations comprising antigens recognized by T cells involved in the pathogenesis of T cell mediated diseases, such as autoimmune diseases, and a metabolizable lipid emulsion as a biologically active carrier.
Autoimmune disorders, e.g., insulin-dependent diabetes mellitus (IDDM or type I diabetes), multiple sclerosis, rheumatoid arthritis and thyroiditis, are characterized by reactivity of the immune system to an endogenous antigen, with consequent injury to tissues. These immune responses to self-antigens are maintained by the persistent activation of self-reactive T lymphocytes.
T cells of the CD4 xe2x80x9chelperxe2x80x9d type have been divided into two groups by the characteristic cytokines they secrete when activated (Mosmann and Coffman, 1989). TH1 cells secrete IL-2, which induces T cell proliferation, and cytokines such as IFN-xcex3, which mediate tissue inflammation. TH2 cells, in contrast, secrete IL-4 and IL-10. IL-4 helps T cells secrete antibodies of certain IgG isotypes and suppresses the production of TH1 inflammatory cytokines (Banchereau et al., 1994). IL-10 indirectly inhibits TH1 activation by affecting antigen-presentation and inflammatory cytokine production by macrophages (Moore et al., 1993). It is the TH1 cells which contribute to the pathogenesis of organ-specific autoimmune diseases. TH1-type responses also appear to be involved in other T cell mediated diseases or conditions, such as contact dermatitis (Romagnani, 1994).
Peptides suitable for immunologically specific therapy of an autoimmune disease are peptides that are recognized by T cells involved in the pathogenesis of the autoimmune disease. Each autoimmune disease will have its ideal peptide for use in therapy. A disease like multiple sclerosis involving T cells reactive to self-antigens such as myelin basic protein (MBP) (Allegreta et al., 1990) will require a peptide of myelin basic protein for its therapy, as for example those described by Ota et al., 1990.
The present inventors have shown that autoimmune diseases such as type I diabetes mellitus may be treated by administering a suitable peptide in an oil vehicle. NOD mice spontaneously develop type I diabetes caused by autoimmune T cells that attack the insulin-producing xcex2 cells of the islets. The autoimmune attack is associated with T-cell reactivity to a variety of self-antigens including a peptide of the 60 kDa heat shock protein (hsp 60) and peptides of glutamic acid decarboxylase (GAD). Thus, for example, spontaneous diabetes developing in the NOD/Lt strain of mice could be treated with a peptide designated p277 corresponding to positions 437-460 of the human hsp 60 sequence (PCT Patent Publication No. WO90/10449; D. Elias and I. R. Cohen, Peptide therapy for diabetes in NOD mice, The Lancet 343:704-06, 1994); with variants of the p277 peptide in which one or both cysteine residues at positions 6 and/or 11 have been replaced by valine and/or the Thr residue at position 16 is replaced by Lys (see PCT Publication WO96/19236) and with peptides designated p12 and p32 corresponding to positions 166-185 and 466-485, respectively, of the human hsp60 sequence. See Israel Patent Application No. 114,407 of the same applicant of the present application, filed on Jun. 30, 1995. See also PCT application No. PCT/US96/11375, filed Jul. 1, 1996, claiming priority from said Israel application no. 114,407, the entire contents of which are hereby incorporated by reference.
Peptide therapy for treatment of IDDM using p12, p32, p277 or variants thereof, was found by the present inventors to be effective when the peptide was administered to mice subcutaneously (sc) in an oil vehicle such as an emulsion of mineral oil known as incomplete Freund""s adjuvant (IFA). However, IFA as well as complete Freund""s adjuvant (CFA; a preparation of mineral oil containing various amounts of killed organisms of Mycobacterium) are not allowed for human use because the mineral oil is not metabolizable and cannot be degraded in the body. Therefore, it would be desirable to discover an effective vehicle for peptide therapy that would be metabolizable.
Several fat emulsions have been in use for many years for intravenous nutrition of human patients. Two of the available commercial fat emulsions, known as Intralipid (xe2x80x9cIntralipidxe2x80x9d is a registered trade mark of Kabi Pharmacia, Sweden, for a fat emulsion for intravenous nutrition, described in U.S. Pat. No. 3,169,094) and Lipofundin (a registered trade mark of B. Braun Melsungen, Germany) contain soybean oil as fat (100 or 200 g in 1,000 ml distilled water: 10% or 20%, respectively). Egg-yolk phospholipids are used as emulsifiers in Intralipid (12 g/l distilled water) and egg-yolk lecithin in Lipofundin (12 g/l distilled water). Isotonicity results from the addition of glycerol (25 g/l) both in Intralipid and in Lipofundin. These fat emulsions are quite stable and have been used for intravenous nutrition of patients suffering from gastrointestinal or neurological disorders, which prevent them from receiving nutrition orally, and thus they receive the calories needed to sustain life. Usual daily doses are of up to 1 liter daily.
U.S. Pat. No. 4,073,943 issued on Feb. 14, 1978 to Wretlind et al. and U.S. Pat. No. Re. 32,393 issued on May 29, 1990 as reissue patent of U.S. Pat. No. 4,168,308 issued on Sep. 18, 1979 to Wretlind et al., describe a carrier system for use in enhancing parenteral, particularly intravenous, administration of a pharmacologically active, oil-soluble agent, comprising a stable, oil-in-water emulsion containing a pharmacologically inert lipoid as a hydrophobic phase dispersed in a hydrophilic phase, said lipid being dispersed in the emulsion as finely divided particles having a mean particle size less than 1 micron to achieve rapid onset of an acceptable therapeutic effect, said carrier system being used with an effective dose of said pharmacologically active, oil-soluble agent predominantly dissolved in said lipoid at a fraction ratio thereto in the hydrophobic phase, said therapeutic effect being attributable to said effective dose of the active agent. This carrier system is said to be suitable for administration of a water-insoluble or water-soluble, oil-soluble pharmacologically active agent that is predominantly dissolved in the lipoid phase. Examples of such pharmacologically active agents are depressants, anaesthetics, analgesics, stimulants, spasmolytics, muscle relaxants, vasodepressants and diagnostic, e.g. X-ray contrast, agents. The carrier system is said to enhance the diagnostic or therapeutic effect of the agent with a rapid onset accompanied by a reduced incidence of injury to body tissues.
Intralipid has been proposed as a non-irritating vehicle for several adjuvants for use in vaccines such as, for example, 6-O-(2-tetradecylhexadecanoyl)- and 6-O-(3-hydroxy-2-docosylhexacosanoyl)-N-acetylmuramyl-L-alanyl-D-isoglutamine (Tsujimoto et al., 1986 and 1989), avridine (Woodard and Jasman, 1985), N,N-dioctadecyl-Nxe2x80x2,Nxe2x80x2-bis(2-hydroxyethyl) propanediamine (CP-20,961) (German Patent Application No. DE 2945788; Anderson and Reynolds, 1979; Niblack et al., 1979). Kristiansen and Sparrman, 1983, have disclosed that the immunogenicity of hemagglutinin and neuraminidase in mice is markedly increased after adsorption onto lipid particles constituting Intralipid.
None of the above publications describe the use of Intralipid as a vehicle for peptides in the treatment of autoimmune diseases, nor has there been any disclosure that Intralipid could mediate a shift of the immune response from a TH1-type response to a TH2-type response.
It has now been found, in accordance with the present invention, that metabolizable lipid emulsions, such as Intralipid and Lipofundin, can act as vehicles for peptide therapy of autoimmune diseases and of other TH1 T cell mediated diseases or conditions. It has been further found that this activity is associated with a TH1 to TH2 cytokine shift.
The present invention thus relates to a therapeutic preparation for the treatment of an autoimmune disease or other T cell mediated disease or condition, comprising a peptide or other antigen and a biologically active lipid carrier, wherein the peptide or other antigen is one recognized by inflammatory T-cells associated with the pathogenesis of said disease or condition, and wherein the biologically active lipid carrier is a fat emulsion comprising 10-20% triglycerides of plant and/or animal origin, 1.2-2.4% phospholipids of plant and/or animal origin, 2.25-4.5% osmo-regulator, 0-0.05% anti-oxidant, and sterile water to 100%.
The triglycerides and phospholipids of plant or animal origin may derive from any suitable vegetable oil, such as soybean oil, cottonseed oil, coconut oil or olive oil, or from egg-yolk or bovine serum. Preferably, the triglycerides are derived from soybean oil and the phospholipids are derived from soybean or from egg-yolk. Preferably, the triglycerides/phospholipids weight ratio is about 8:1.
Any suitable osmo-regulator may be added to the fat emulsion, preferably glycerol, xylitol or sorbitol. The fat emulsion may optionally comprise an anti-oxidant, for example 0.05% tocopherol.
In one embodiment of the invention, the fat emulsion as defined above is processed by centrifugation, e.g. at 10,000 g or higher, thus forming a small triglyceride-rich (about 90% triglycerides) layer on the top of a phospholipid-enriched aqueous dispersion containing about 1:1 triglycerides:phospholipids, and this latter aqueous dispersion is used as the lipid vehicle in the preparations of the invention.
In one preferred embodiment of the invention, the preparation is for the treatment of insulin-dependent diabetes mellitus (IDDM) and comprises a peptide derived from the human heat shock protein 60 (hsp60) that is recognized by inflammatory T-cells associated with the pathogenesis of IDDM, wherein said peptide is selected from the group of peptides appearing in the following Table 1:
The invention further relates to a method for therapy of a subject suffering from an autoimmune disease or other TH1 mediated disease or condition, which comprises administering to said subject an effective amount of a therapeutic preparation according to the invention.